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United States Patent SULFOSUCCINATE ESTERS OF FATTY ACID MONO- AND DIGLYCERIDES Jack T. Thurston,'Riverside, Conrn, assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application February 25, 1953, Serial No. 338,917

9 Claims. (Cl. 117-1395) This invention relates to a new class of compounds which-have outstanding characteristics as non-yellowing,

softening agents for cotton and rayon textiles during hot finishing treatments and storage thereof. More particularly, the invention relates to a class of sulfosuccinic acid bis-esters of higher fatty acid glycerides possessing these desirable characteristics. The invention includes the novel softening agents, the methods of preparing the same, the method of softening textiles therewith, and the :thereby improved textile products. manufacture and finishing, cotton and rayon textiles are pounds hitherto employed by the art have been sulfonated hydrocarbons, waxes, stearates, and sulfated oils such as cottonseed oil, peanut oil, and similar oil products.

In view of the economics involved in textile manufacture, some of the most widely employed softening agents have been sulfated and/orsulfonated tallow, and sulfated and/or sulfonated monoand diglycerides of tallow, cottonseed oil, coconut oil and other compounds containing the relatively long carbon chain of the higher fatty acids. However, it has been noted that'the incorpora- 'tion of even small amounts of these agents in cotton and rayon textiles has resulted in an undesirable yellowing of the fabric subsequent to the finishing thereof.

This is primarily due'to the fact that the washed and/or sized fabrics are ordinarily dried at temperatures of about 250-400" F. and are then immediately rolled'into bolts. The inner'layers of the'bolted cloth retain theheat for a 'periodof several days during which time these sulfated or sulfonated softening agents, substantially all of which are. relatively sensitive to heat, deteriorate sufliciently-to cause serious yellowing of the treated fabric. Similarly, in the fabrication of garments'from the treated textile materials, the cloth is frequently subjected to hot pressing operations at elevated temperatures which cause these softening agents to deteriorate. Therefore, although sulfated and sulfonated fatty acids and fatty acid .glycerides are recognized as outstanding textile softening agents, their lack of heat stability has rendered them unfit for many textile finishing operations.

It has now been discovered, quite unexpectedly, that the members of a new class of bis-esters of sulfosuccinic acid :and- .glycerides ofhigher fatty acids derived from'particu lar sources possess outstanding textile softeningproper- In the course of their ties without any appreciable tendency to deteriorate under the influence of heat and bring aboutyellowing. In addition to these desirable qualities, this class of compounds has also been found to :plasticize the starch sizes which are employed by the textile industry. Thus, the novel ciass of compounds of this invention provides'the textile industry with a dual-purpose agentwhich acts both as ,a

non-yellowing, textile-softening compound and a plasticizer for starch-sized fabrics.

A further important advantage of the invention resides in the fact that all ofithe starting materials of the'bis-esters of sulfosuccinic acid are readily available commercially at relatively low-cost and,.as.pointed out" above, this feature is extremely attractive-totthe manufacturers of textiles.

The novel class of non-yellowing textile softening agents-off the present invention are .believed to have the following general structural formulae:

metals and ammonium.

The following animal and vegetable oils andfats are set forth as illustrative but notlimitative of.the type .of

oil or fat used as a selective source of the-higher fatty acid glycerides: the vegetable oils, suchas .coconut 'oil;

palm kernal oilg'ouri-curi oil; ucuhuba oil, tea seed oil;

olive oil; and palm oil; the animal fats .such .as lard, greases, Chinese tallow, mutton tallow and beef tallow; neats foot'oil; etc.

It'Lis to be-particularly observed that these oleaginous materials do not possess any substantial amounts of "hydroxy acids; that they contain less than about 15%-by Weight of polyunsaturated fatty acids; haverelatively low .iodirie values (the quantity of'iodine in'mg. absorbed by 1 gm. of oil under normal conditions); and basically possess a non-drying nature.

.Hydrogenated oils which do not contain any interfering hydroxygroups (such as in castor oil) may be used, provided the unsaturation of the fatty acids therein is reduced to below the above-mentioned 15% value-andto correspondingly low iodine values. Such oils would include: hydrogenated cottonseed oil; hydrogenated corn oil; hydrogenated peanut oil; hydrogenated soya bean oil; hydrogenated sunflower seed ,oil;'hydrogenated sesameoil; hydrogenated kapok oil; hydrogenated rapeseed oil;hydrogenated tung oil; etc.

Although these oils and fats contain fatty acids having various carbon chain lengths,'the chain length of particular use within the concepts of thepresent invention 1 18. carbon atoms,

be the reaction product resulting from the use of 100% pure monoglycerides. A mixture of monoglycerides and diglycerides is normally commercially present and it has been found that a molar ratio of these two constituents within the range of about 50-95% of monoglyceride and about 505% of diglyceride is well adapted for application to the principles of the present invention. The presence of diglycerides in greater proportions than about 50%, however, undesirably decreases the water solubility characteristics of the compound and is to be avoided.

Briefly, the sulfosuccinic acid bis-esters are prepared by means of a three-step process. The monoglyceride (or the mixture of monoand diglycerides) is prepared by reacting the selected animal or vegetable oil or fat with an excess of glycerol in the presence of a basic material such as an alkali or alkaline earth or heavy metal oxide or hydroxide, such as sodium hydroxide, calcium hydroxide or lead oxide. After the reaction to form the monoglyceride is complete, the basic catalyst is removed by precipitation as a fumarate salt.

In order'to prevent the formation of an insoluble resin which is believed to be a cross-linked glycerol-maleic or furnaric ester, it is necessary to heat treat the monoglyceride in the presence of at least mole percent of added fatty acid, e. g., stearic, palmitic, or oleic acid or their equivalents. A time of at least one hour and temperature of about 100-150 C. is desirable for this heat treatment.

The resulting heat-treated monoglyceride is then condensed with approximately one-half of an equimolar amount of maleic anhydride, or fumaric acid, or maleic acid to obtain the corresponding fumarate (maleate) bisester. This condensation product is then sulfonated by use of a bisulfite or metabisulfite containing a cationic salt-forming substituent, such as any of the alkali metals or ammonium. Preferably, the sulfonation is carried out by heating the bis-ester with an aqueous solution of alkali metal or ammonium bisulfite or metabisulfite whereby the corresponding salt is obtained directly.

Salts of other bases may be readily obtained by first acidifying an alcoholic solution of the alkali metal or ammonium salts whereby the free bis-ester of sulfosuccinic acid is obtained, filtering oft the inorganic salt of the acid used and reacting the acid with the desired base. Although they are not ordinarily employed in textile finishing treatments, salts of the polyvalent metals such as calcium, barium, zinc, lead, cadmium, and the like may be prepared, if desired, by adding stoichiometric quantities of their oxides or hydroxides to the alcoholic sulfosuccinic acid ester solution followed by stirring until the salt formation is complete. such 7 as methyl, ethyl, or butyl amine; guanylurea; quanidine; hydroxyethylguanidine; biguanide; ethanolamine; triethanolamine; or higher aliphatic amines; aromatic amines; and heterocyclic bases such as nicotine, pyridine, quinoline; and alkaloids may also be prepared by the same method as well as by direct sulfonation employing the sulfites and bisulfites of the organic bases. The invention will be further illustrated in greater detail by the following specific examples. It should be understood, however, that although these examples may describe in particular detail some of the more specific features of the present invention, they are given primarily for purposes of illustration and the invention in its broader aspects is not to be construed as limited thereto.

EXAMPLE 1 Salts of organic bases Step 1.-Preparati0n 0f tallow monoglyceride The first three materials were charged to a 100-gal., stainless-steel kettle. By means of liquid Dowtherm heating, the temperature of the reaction mixture was raised to and maintained at approximately 235 C., while nitrogen was passed into the kettle at a rate of from about 5 to about 6 liters per minute. When the methanol tolerance (the number of ml. ofmethanol per number of ml. of reaction mixture which produces an incipient cloudiness) had become constant at about 2 /2 to 3 hours at 235 C., the batch was cooled to 150 C.

The fumaric acid and 1% by'weight of Hyflo were then added and, after 15 minutes agitation, the slurry was put through a 5-gal., stainless-steel, steam-jacketed, Sparkler filter. .The filtrate was run into a lOO-gaL, stainless-steel pot and stirred for 24 hours in an oven at C. The first 40 lbs. (the lower layer) was drawn off and set aside as this portion usually contained the bulk of the excess glycerol.

The monoglyceride resulting from Step 1 and the stearic acid were charged to a -gal., stainless-steel kettle equipped with liquid Dowtherm heating, propellertype stirrer, nitrogen gas inlet tube, and a stainless-steel condenser fitted with a water trap. The charge was heated to and maintained at approximately C. for two hours while passing nitrogen through the reaction mixture at the rate of about 4 liters per minute. The fumaric acid and xylene were then added and the temperature was raised to approximately C. After 5 v to 6 hours, all of the fumaric acid had reacted and the temperature had reached -l95 C. An amount of water usually somewhat in excess of the theoretical amount was collected in the trap. The xylene was stripped off at 160 C. and then finally at 160 C. at a reduced pressure of 30 mm. The batch was cooled to 120 C. and discharged into a SO-gal. receptacle.

The product was a moderately viscous brown liquid at 120 C. and a light tan waxy solid at room temperature. The acid number of several preparations varied between 10 and 2-.

Step 3.-Sulfnati0n of the fumaric acid ester l The amount of sodium sulfite added is determined by the acid number of the charge. The amount of sodium bisulfite added is such as to give a total of 110% of theory. This total includes the NaHSOz derived from the NazSOa.

The bis tallow monoglyceride fumarate, sodium sulfite, ethanol, and water were charged to a 200-gal., stainless-steel jacketed kettle equipped with a turbo-agitator and a stainless-steel condenser which could be used either for reflux or distillation. The charge was refluxed for approximately minutes. At the end of this period,

the sodium bisulfite was added and the batch was maintained at a reflux temperature of approximately 80 C. for about 12-19 hours. The sulfonation, as determined by an iodine titration of the excess bisulfite, was usually substantially complete and was in the range of about 90l00%. The batch was cooled to C. and the calculated amount of hydrogen peroxide was added to oxidize the free bisulfite to bisulfate. The pH'of-the batch was then brought up to approximately 6.0-6.5 by the addition of either 10 or 20% sodium hydroxide solution. The mixture was concentrated to 8085% solids to remove the ethanol, diluted with water to about solids and discharged into 50-gal. containers. At C. the product was a moderately viscous tan liquid which hardened to a stiff tan paste at room temperature.

EXAMPLE 2 The procedure set forth in Example 1 was repeated with mutton tallow being substituted for the beef tallow.

The mutton tallow had an iodine value of 57.0, a saponification value of 196 and a solidifying point of 39 C. The mutton tallow contained approximately 5.5% by weight of polyunsaturated fatty acids, primarily octadccadienoic acid.

The reactions were substantially as described in Example l and the product was a moderately viscous tan liquid at elevated temperatures, hardening to a solid stifi' tan paste at room temperature.

EXAMPLE 3 A sulfosuccinic acid bis-ester of coconut oil monoglyceride was prepared from a coconut oil having an iodine value of 7.2; a saponification value of 259; and a solidifying point of 16 C. The oil contained approximately 2.9% by weight of polyunsaturated fatty acids, primarily linoleic acid.

Step A.-Preparati0n of coconut oil monoglyceria'e liquid.

droxide solution. -tion under reduced pressure and the percent solids was 'fumaric acid equivalent to thecalcium oxide was added and, after a 'shortinterval 'of 15 minutes, the calcium fumarate thus precipitated was removed by filtration. The filtered productwas allowed to stand at about C. for approximately 3-6 hours and the glycerol which separated was removed. The finalproductwas a .pale

' tan, viscous. liquid.

Step 'B.-Prepamti0n of bis-coconut oil monoglyceride fumarate Coconut oil monoglyceride, 556 g. (2.0 moles) and stearic acid, 112 g. (0.4 mole) were placed in a two-liter, three-neck flask, fittedas described in Step A, and heated to and maintained at C. for two hours. At the end of this period, fumaric acid, 116 g. (1.0 mole), and 100 ml. xylene were added. The temperature was raised to and maintained at 175-'-180C. until at least the theoretical amount of water of'reaction had been obtained; 'The xylene Was removed by distillation under reduced'pressure. The product, acid number 105, was a'tanviscous Step C.Sulf0nati0n of the bis-coconut oil monoglyceride fumarate Bis-coconut oil monoglyceride fumarate (from Step B) 748 g., together with 17.7 g. (0.14 mole) of NazSO3,'l2-5 g. of ZB-alcohol and g. of water were placed in a three-liter, three-neck flask fitted with condenser and stirrer. Heating was by means of a steam bath; After 15 minutes of refluxing, 99.4 g. of NaHSOz (0.955 mole) was added and refluxing was continued until the sulfona- -tion was at least 85% complete, as determined by titration of the unreacted sodium bisulfite present in the reaction mixture. The excess sodium bisulfite was oxidized to bisulfate with hydrogen peroxide and the pH of the reaction mixture was raised too-6.5 with sodium hy- The alcohol was removed by distillaadjusted to 75% by addition of water. The-product was a tan, viscous liquid. 1

EXAMPLE 4 The procedure set forth in Example 3 was repeated with olive oil being substituted for the coconut oil. The olive oil had an iodine value of 79; a saponification value of 194; a solidifying point of 1 C.; and contained approximately 13.6% by weight of polyunsaturated fatty acids, primarily linoleic. acid.

The-reactions were substantially as described in Example 3 and the product was a moderately viscous tan liquid at elevated temperatures, forming'a soft paste :at room temperature.

In employing the novel bis-esters of the invention in textile softening treatments, a dispersion of from about 0.5% to about 3% or more of the selected bis-ester is prepared in a water bath or, if the textile is to be sized at the same time, in an aqueous size bath. The textile material is thereafter impregnated in the bath to a wet pickup of substantially 100% of the weight of fabric and then dried according to normal operating procedure. Ordinarily, where no sizing agent is employed it is unnecessary to have more than about 1% of the softening agent on the fabric in order to obtain the desired softness of hand in the product. On the other hand, where a sizing agent is used, it is sometimes necessary to increase the softening agent content to about 3% or more to obtain the desired improvement in softness of hand in the treated fabric.

The sulfosuccinic acid bis-esters of higher fatty acid glycerides of the present invention have been evaluated to determine their non-yellowing and softening properties and the following results have been obtained. The test samples were diluted from their 70-80% solid wax-like form to approximately 35% pastes and formed uniform white pastes with no ditficulty. Several 1% solutions of various 35% pastes were padded onto 80 x 80 cotton percale fabrics and compared to similar fabrics padded with a standard softener currently sold in large quantities on the open market. Hand evaluation for softness showed that the fabrics treated with the product of the present invention were consistently softer and possessed a fuller feel. 1

In order to test the non-yellowing characteristics of the present product, several pieces of rayon and cotton containing 1% finish were heated to and maintained at 95 C. for 72 hours in sealed jars. Reflectance measurements before and after heating showed considerably less yellowing, when compared to the yellowing obtained by the use of a standard non-yellowing softener currently sold in large quantities on the open market.

Although I have described several specific examples of my inventive concept, I consider the same not to be limited thereby nor to the specific substances mentioned therein, but to include various other compounds of equivalent constitution as set forth in the claims appended hereto. It is understood that any suitable changes, modifications and variations may be made without departing from the spirit and scope of the invention.

I claim:

1. A bis-ester of sulfosuccinic acid with a substantially bi-molecular quantity of a member of the group consisting of higher fatty acid monoglycerides, higher fatty acid diglycerides, and mixtures thereof derived from a member of the group consisting of the animal and vegetable oils and fats containing less than 15% by weight of polyunsaturated fatty acids.

2. A bis-esteras defined in claim 1, wherein the higher fatty acid glyceride comprises a mixture of from about 50% to about 95% monoglyceride and from about 50% to about 5% diglyceride, said percentages being on a molar basis.

3. A bis-ester of sulfosuccinic acid with a substantially bi-molecular quantity of a member of the group consisting of higher fatty acid monoglycerides, higher fatty acid diglycerides, and mixtures thereof derived from tallow.

4. A bis-ester of sulfosuccinic acid with a substantially bi-molecular quantity of a stearic acid monoglyceride.

5. A sulfosuccinic bis-ester of a fatty acid glyceride having the following formula:

6. A sulfosuccinic bis-ester of a fatty acid glyceride having the following formula:

wherein R is a higher fatty acid radical derivable from a member of the group consisting of animal and vegetable oils and fats containing less than 15% by weight polyunsaturated fatty acids; and Me is a salt-forming cation of the group consisting of alkali metals and ammonium.

7. A method of preparing a sulfosuccinic acid bis-ester of a higher fatty acid glyceride which comprises esterifying a member of the group consisting of higher fatty acid monoglycerides, higher fatty aciddiglycerides, and mixtures thereof derived from a member of the group consisting of animal and vegetable oils and fats containing less than 15% by weight polyunsaturated fatty acids and a member of the group consisting of maleic anhydride, furnaric acid and maleic acid, and then sulfonating the resulting product by reaction thereof with a water soluble bisulfite.

8. A method of treating textile materials which comprises impregnating the same with a softening and nonyellowing agent comprising a bis-ester of sulfosuccinic acid with a substantially bi-rnolecular quantity of a member of the group consisting of higher fatty acid monoglycerides, higher fatty acid diglycerides, and mixtures thereof derived from a member of the group consisting of the animal and vegetable oils and fats containing less than 15% by weight polyunsaturated fatty acids.

9. A non-yellowing textile material characterized by improved softness of hand comprising a textile material having distributed thereon a bis-ester of sulfosuccinic acid with a substantially bi-molecular quantity of a member of the group consisting of higher fatty acid monoglycerides;

higher fatty acid diglycerides, and mixtures thereof derived from a member of the group consisting of the animal and vegetable oils and fats containing less than 15% by weight polyunsaturated fatty acids.

References Cited in the file of this patent UNITED STATES PATENTS Re. 21,729 Schrauth Feb. 25, 1941 2,184,794 De Groote Dec. 26, 1939 2,570,385 Rust Oct. 9, 1951 

8. A METHOD OF TREATING TEXTILE MATERIALS WHICH COMPRISES IMPREGNATING THE SAME WITH A SOFTENING AND NONYELLOWING AGENT COMPRISING A BIS-ESTER OF SULFOSUCCINIC ACID WITH A SUBSTANTIALLY BI-MOLECULAR QUANTITY OF A MEMBER OF THE GROUP CONSISTING OF HIGHER FATTY ACID MONOGLYCERIDES, HIGHER FATTY ACID DIGLYCERIDES, AND MIXTURES THEREOF DERIVED FROM A MEMBER OF THE GROUP CONSISTING OF THE ANIMAL AND VEGETABLE OILS AND FATS CONTAINING LESS THAN 15% BY WEIGHT POLYUNSATURATED FATTY ACIDS. 